A variety of articles of manufacture are fabricated by cutting, bending and otherwise forming sheet metal. Duct work for heating, ventilating and air conditioning purposes is often times fabricated from sheet metal. Typically, sections having a variety of configurations and dimensions are prefabricated in a shop setting where the prefabrication can be done more easily, more efficiently and more cost effectively. The sections of fabricated sheet metal are then transported to the job site where they are to be installed. The prefabricated sections are set in place, typically by hanging or otherwise supporting the sections on strut channels suspended from the ceiling structure using threaded rods. A nut threaded along rod raises or lowers the strut channel elevation for leveling the ductwork. The sections are then joined one to another, forming a completed system.
A number of methods have been utilized for joining fabricated sections of sheet metal, including screwing, welding and fastening by a variety of mechanical means. One method of joining the prefabricated sections involves forming a flange at the ends of the sheet metal fabrications which are to be joined. The flanges are then butted one up against another and secured by a mechanical clip known as a TDC cleat. The TDC cleat is a mechanical connector formed of sheet metal and is secured to the pair of flanges by hooking a lip formed on the cleat under the edge of the first flange and forcing, by a lever action, the cleat over the outside edge of the second flange. The cleat is formed in such a way that it is approximately 6″ in length and having a first leg with a lip for grabbing the outside edge of the first flange. Opposite the cleat lip is a longer second leg. The cleat first and second legs are joined together by a bridge section. Once the cleat is placed over the two flanges as described above, the second leg is crimped, securing the cleat in place, joining the flange sections.
The TDC cleat is installed with two separate operations: First, an installation or positioning procedure wherein the cleat is snapped over the outside edges of the adjoining flanges, and second, a crimping operation wherein the second leg of the cleat is crimped to secure the connector into place.
These operations or procedures have been accomplished by the use of two separate tools. First, a placement tool having a cross-sectional configuration corresponding to the cross-sectional configuration of the TDC cleat. The placement tool has a lip which secures the cleat for placement over the outside edge of the first flange. The placement tool further comprises a lever means for levering the cleat over the outside edge of the second flange. Once this operation is complete, the placement tool is removed and a separate crimping tool is used for crimping the leg of the TDC cleat to complete the operation. The crimping tool presently used is configured such that it allows crimping only at one point at a time, and the installer must start at one end of the cleat, crimping along the full length of the cleat.
U.S. Pat. No. 5,661,886, the disclosure of which is incorporated by reference in its entirety, describes a combination clip or cleat installation and crimping tool, that is used to install the clip over the edges of the two flanges, and then to crimp the second leg of the clip. Notwithstanding, there remains a need for improved tools for the installation of ductwork, including the placement and crimping of cleats and the positioning and leveling of the ductwork.